ASAP addresses a fundamental bottleneck in marine glycobiology: the lack of defined oligosaccharide substrates needed to decode how marine bacteria degrade algal polysaccharides and thereby regulate carbon storage in the ocean. Marine algae fix gigatonnes of CO2 annually, storing much of this carbon in structurally complex, often highly sulfated polysaccharides. Their microbial breakdown, driven by specialized carbohydrate-active enzymes (CAZymes), determines whether carbon is rapidly remineralised or sequestered for millennia in deep-sea sediments. Studying these enzymatic pathways is challenging because algal polysaccharides are large, heterogeneous, and synthetically inaccessible.
ASAP overcomes this barrier by using Automated Glycan Assembly (AGA) to produce unprecedented libraries of structurally defined marine oligosaccharides representing all major polysaccharide classes, including carrageenans, fucoidans, alginates, agarans, porphyrans, ulvans, xylans, and laminarins. The project develops new AGA methodologies for challenging 1,2-cis linkages, uronic acids, and high-density sulfation to enable the automated synthesis of complex anionic glycans.
These synthetic tools will allow systematic functional analyses of polysaccharide degradation by (i) seawater and sediment microbial communities, (ii) cultured marine bacterial strains, and (iii) purified individual CAZymes. Using fluorescently labelled oligosaccharides and high-resolution HPLC-MS, ASAP will map substrate specificities and enzymatic pathways involved in marine carbohydrate turnover.
